Characterization of translation factor aIF5A in the crenarchaeum Sulfolobus solfataricus

Translation factor a/eIF5A is highly conserved in Eukarya and Archaea, with an orthologue (EF-P) in bacteria. It has been shown that the eukaryal protein is required for transit of ribosomes across consecutive proline codons, whereas the function of the archaeal orthologue remains puzzling. Here, we provide evidence for the involvement of Sulfolobus solfataricus (Sso) aIF5A in translation. CRISPR-mediated knockdown of the aif5A gene resulted in strong growth retardation, underlining a pivotal function. Moreover, in vitro studies revealed that Sso aIF5A is endowed with endoribonucleolytic activity.